A 13,000 year old skeleton could have 'major implications' for origins of American peoples

Divers Alberto Nava and Susan Bird transport the Hoyo Negro skull to an underwater turntable so that it can be photographed in order to create a 3-D model.

The skeletal remains of teenage girl who fell to her death in the last Ice Age could have “major implications” for our understanding of the origins of the first Americans, say scientists.

Divers in Mexico discovered the near-complete skeleton by accident while exploring an underwater cave system in the Yucatan peninsula. Named Naia after the water nymph of Greek mythology, the girl is thought to have died after falling into the cave (which is thought to have been dry at the time).

The discovery was made back in 2007 by professional divers who were mapping the water-filled complex and came across the massive chamber underground.

"The moment we entered inside, we knew it was an incredible place," one of the divers, Alberto Nava, told reporters. "The floor disappeared under us and we could not see across to the other side."

The divers named the place Hoyo Negro or black hole and returned months later to explore the floor of the 100-foot deep chamber. They found it littered with the bones of giant ground sloths and sabre-tooth cats, suggesting that the promise of finding water had lured both the animals and Naia to their deaths in the cave.

“It was a small cranium laying upside down with a perfect set of teeth and dark eye sockets looking back at us,” said Nava, describing the find of the skeleton. “The skull was resting on its humerus and we could see the rest of the upper torso spread to the left and down on the ledge."

After its retrieval, researchers used a combination of carbon dating methods to date the remains, describing it as “clearly the most complex skeleton older than 12,000 years," including “all of the major bones of the body and an intact cranium and set of teeth.”

Divers Susan Bird and Alberto Nava search the walls of Hoyo Negro, an underwater cave on Mexico’s Yucatán Peninsula where the remains of Naia were found.

The find could settle a long-standing debate as to the origins of the first Americans. It’s previously been suggested that the earliest settlers on the continent, known as palaeoamericans, could have come from different ancestry to modern Native Americans.

It’s known that modern Native Americans are descendants of hunter-gathers who lived in Siberia around the Bering Strait some 18,000 to 26,000 years ago, who crossed using a now submerged land bridge between Asia and Alaska around 17,000 years ago before spreading south.

However, the characteristics of the oldest paleaoamericans remains differ from those of modern Native Americans, with some scientist suggesting this means they came from different parts of the world – Australia, southeast Asia or possibly even Europe.

Genetic material extracted from Naia’s bones shows that this theory is likely incorrect, with DNA found in her molar containing a distinctive marker found only in the native peoples of Chile and Argentina. This suggests that early American and contemporary populations do indeed share ancestral roots, with any anatomical differences reflecting evolution over time in Beringia or the Americas.

"What this study is presenting for the first time is evidence that palaeoamericans, with those distinctive features, can also be directly tied to the same Beringian source population as contemporary Native Americans," said Deborah Bolnick, co-author of a paper published in Science detailing the findings.